Synthesis Of Triphenodioxazine Pigments

ABSTRACT

The invention relates to a process for the preparation of compounds of the general formula (I) where X are halogen atoms, the rings labeled A are linearly or angularly fused in position 1,2; 2,3 or 3,4, and in position 8,9; 9,10 or 10,11, to a 5- or 6-membered heterocyclic ring containing in the ring one nitrogen atom and one oxygen atom, or containing in the ring two nitrogen atoms, comprising an oxidation of a 3,6-bisarylamino-2,5-dihalobenzoquinone of the formula (II) in an aprotic-polar organic solvent in the presence of an organic sulfonic acid.

The invention relates to a particularly advantageous process for thepreparation of triphenodioxazine compounds by oxidative ring closure inaprotic-polar organic solvents.

U.S. Pat. No. 5,565,563, DE-A-44 42 291, and EP-A-0 889 046 describetriphenodioxazine compounds of the following general formula

whereX represents hydrogen or halogen atoms.

The rings labeled A carry rings which are fused linearly or angularlyand consist of radical members, among others, of the formulae—NR₁—(CO)_(m)—NH—, —NR₁—(CO)—O—, or —CR₁═CH—CO—NH—.

These compounds are particularly useful as pigments for coloringplastics including both solvent-free and solvent-containing masses ofplastics or plastic resins. These include oil-based or aqueous paintsystems and lacquers of various kinds. These compounds are also suitablefor spin coloring of viscose or cellulose acetate, for pigmenting ofpolyethylene, polystyrene, polyvinylchloride, rubber or artificialleather. They can also be used for printing graphic fabrics, forcoloring paper masses, for coating of textiles or for any other pigmentprinting process. The resulting pigmentations have excellent fastness toheat, light and weathering and chemicals. The pigments retain goodstrength of color and have good application properties. In particular,they have good fastness to migration, blooming, overcoating andsolvents.

The preparation process disclosed in U.S. Pat. No. 5,565,563 and EP-A-0889 046 starts from intermediates i.e. amino compounds, which areortho-substituted by an alkoxy group and are obtainable only by way of arelatively complex synthesis.

The preparation process disclosed in DE-A-44 42 291 starts fromunsubstituted amino compounds, which are easily obtainable. The pigmentsynthesis is performed with manganese dioxide in concentrated sulfuricacid and requires the isolation of intermediate products. An aftertreatment of the crude pigment in an organic solvent is often necessaryto obtain the required pigment properties.

The object of the invention is to provide a novel process for producingtriphenodioxazine pigments of formula (I) in high yields.

It was found surprisingly that these pigments can be prepared byoxidation of the respective 2,5-bisarylamino-1,4-benzoquinones inaprotic-polar solvents, but only in the presence of an organic acid.This finding was very surprising because the same process does not workresult-effectively with triphenodioxazines of the PV 23 type.

The present invention therefore provides a process for the preparationof compounds of the general formula (I)

whereX represents halogen atoms, preferably chlorine or bromine, especiallychlorine;the rings labeled A are linearly or angularly fused in position 1,2; 2,3or 3,4, and in position 8,9; 9,10 or 10,11 to a 5- or 6-memberedheterocyclic ring containing in the ring one nitrogen atom and oneoxygen atom, or containing in the ring two nitrogen atoms,comprising an oxidation of a 3,6-bisarylamino-2,5-dihalobenzoquinone ofthe formula (II)

in an aprotic-polar organic solvent in the presence of an organicsulfonic acid.

Preferred compounds of formula (I) are those with formulae (Ia), (IIa),(IIIa) and (IIIb)

where X is hydrogen or halogen, R₁, R₂, R₃ and R₄, independently fromone another, are hydrogen, a C₁₋₈ alkyl radical, a substituted orunsubstituted phenyl, benzyl, benzanilide or naphthyl radical, asubstituted or unsubstituted C₅₋₆ cycloalkyl radical.

The substituents R₁, R₂, R₃ and R₄, independently from one another, arepreferably hydrogen, a methyl radical, an ethyl radical, an n- oriso-propyl radical, a n-, iso-, sec- or tert-butyl radical, a cyclohexylradical, a substituted or unsubstituted benzanilide radical, a naphthylradical, an unsubstituted phenyl radical, a phenyl radical substitutedone or more times by radicals selected from the group consisting ofhalogen, preferably chlorine, nitro, C₁₋₈ alkyl radicals, preferablyC₁₋₈ alkyl radicals, and C₁₋₈ alkoxy radicals.

Examples for aprotic-polar organic solvents which can be used in thepresent process are ethers, esters, ketones, amines, nitromethane,chlorobenzenes, and chlorotoluenes. Advantageous are chlorobenzene,1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 2-chlorotoluene, 3-chloro toluene, 4-chloro toluene, 2,4-dichloro toluene,3-methyl anisol, 4-methyl anisol, especially 1,2-dichlorobenzene,4-chloro toluene, 2,4-dichloro toluene and 4-methyl anisol. The solventis judiciously used in a 3- to 20-fold amount, preferably 5- to 15-foldamount, based on the weight of the compound of formula (II).

Examples for organic sulfonic acids which can be used in the presentprocess are methane sulfonic acid, benzene sulfonic acid, toluenesulfonic acid and xylene sulfonic acid. The amounts of the organicsulfonic acids can range from 10 to 360 mol %, preferably from 40 to 240mol %, based on the compound of formula (II).

The temperatures of the present oxidation process can be from 20 to 200°C., preferably from 60 to 180° C., particularly from 100 to 170° C.,especially preferred from 120 to 160° C.

Examples for oxidizing and ring closure agents which can be used in thepresent process are aromatic sulfonyl chlorides, such asbenzenesulfonylchloride, toluenesulfonylchloride and chloranil.Especially preferred are mixtures of benzenesulfonylchloride ortoluenesulfonylchloride with chloranil. The amounts of the oxidizing andring closure agents can range from 70 to 240 mol %, preferably from 90to 260 mol %, based on the compound of formula (II).

If a mixture of chloranil with said sulfonylchlorides is used, theamount by weight of chloranil to sulfonylchloride preferably ranges from1:10 to 1:2, especially from 1:3 to 1:5.

The starting compounds of general formula (II) can be prepared bymethods well-known to the skilled artisan, e.g. by a condensationreaction of one equivalent of chloranil with two equivalents of anaromatic amine “H₂N-A-ring system”.

It is also possible to make the compound of formula (I) in a one-potreaction starting from one equivalent of chloranil and two equivalentsof said aromatic amine “H₂N-A-ring system”.

The pigments formed by a process according to the invention are suitablefor the mass pigmentation of suitable substrates including syntheticpolymers, synthetic resins and regenerated fibers optionally in thepresence of solvents. These substrates more particularly include oil,water and solvent based surface coatings, polyester spinning melts,polyethylene, polystyrene and polyvinyl chloride molding materials,rubber, synthetic and natural leather. Furthermore, the pigments can beused in the manufacture of printing inks, for the mass coloration ofpaper and for coating and printing textiles, as well as in the dying ofleather.

When applied to the above-mentioned substrates the pigments are found tobe resistant to migration and fast to light, and show fastness towashing, chlorite, hypochlorite and peroxide bleaching, rubbing,overspraying and solvents. Notably, the pigments display high tinctorialpower, good opacity and good heat stability and high light fastness.

Leather is used in the production of a variety of goods such as shoes,upholstery, garment, and lately in increasing amounts in the automotiveindustry. Leather is used for dashboards, steering-wheel covers, doorpanels, gear lever handles, seat covers and headrests. As the interiorof cars is subject to extreme changes of temperature, intense sunlight,and considerable wear and tear, the pigments employed in the dyingprocess therefore need to fulfill demanding specifications such as: highlight fastness, high heat resistance, high resistance to migration, highperspiration resistance.

There now follows a series of examples which serve to illustrate theinvention.

REFERENCE EXAMPLE6,14-Dichloro-3,11-diethyl-1,3,9,11-tetrahydro-diimidazo[4,5-b:4′,5′-m]-triphenodioxazine-2,10-dionea)2,5-Dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone

90 g of 5-amino-1-ethyl-1,3-dihydrobenzimidazol-2-one and 42 g ofanhydrous sodium hydrogencarbonate are suspended in 1000 g ofdimethylacetamide and the mixture is heated up to 70° C. 62 g ofchloranil are added over 2 h. The mixture is heated under reflux for 1h, cooled down to 100° C., filtered at 100° C., washed with 1000 g ofhot dimethylacetamide and washed with water until free of chloride.Drying at 80° C. under reduced pressure yields 105 g of a brown powderof the following formula

Yield 81%

b)6,14-Dichloro-3,11-diethyl-1,3,9,11-tetrahydro-diimidazo[4,5-b:4′,5′-m]triphenodioxazine-2,10-dioneby oxidation with air (WO 2002046315)

53 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1′,4-benzoquinone(as obtained in Example 1a) and 28 g of potassium carbonate aresuspended in 400 g of dimethylacetamide and the mixture is heated up toreflux. Under inlet of air (ca. 501/h) the mixture is refluxed for 10 h,filtered at 100° C., washed with 400 g of hot dimethylacetamide andwashed with water until free of chloride. Drying at 80° C. under reducedpressure yields 21 g of a green-metallic powder of the following formula

Yield 40%

EXAMPLE 1

132 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 10 g of chloranil aresuspended in 1250 g of 1,2-dichlorobenzene. The mixture is then heated.Between 80-100° C. there are added 40 g of methanesulfonic acid. Ataround 135-140° C. there are added 45 g of benzenesulfonyl chloride. Thereaction mixture is then heated to 145° C. for 4 hours, cooled to 100°C. and collected by filtration. The filter cake is washed with 1.5 L ofhot 1,2-dichlorobenzene and then suspended in boiling water, collectedby filtration and washed with water until free of chloride. Drying at80° C. yielded 114 g of a green-metallic powder of the followingformula.

Yield: 87.3%

EXAMPLE 2

13.2 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 1.25 g of chloranil and 1 gof sodium 2,5-dimethylbenzenesulfonate are suspended in 125 ml of1,2-dichlorobenzene. The mixture is then heated. Between 80-100° C.there are added 4 ml of methanesulfonic acid. At around 135-140° C.there are added 4.5 ml of benzenesulfonyl chloride. The reaction mixtureis then heated to 145° C. for 4 hours, cooled to 100° C. and collectedby filtration. The filter cake is washed with 150 ml of hot1,2-dichlorobenzene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 12.2 g of a green-metallic powder of the following formula.

Yield: 93.1%

EXAMPLE 3

13.2 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 3.1 g of sodium2,5-dimethylbenzenesulfonate are suspended in 125 ml of 4-chlorotoluene.The mixture is then heated. Between 80-100° C. there are added 4 ml ofmethanesulfonic acid. At around 135-140° C. there are added 4.5 ml ofbenzenesulfonyl chloride. The reaction mixture is then heated to 145° C.for 4 hours, cooled to 100° C. and collected by filtration. The filtercake is washed with 150 ml of hot 4-chlorotoluene and then suspended inboiling water, collected by filtration and washed with water until freeof chloride. Drying at 80° C. yielded 12.1 g of a green-metallic powderof the following formula.

Yield: 92.4%

EXAMPLE 4

13.2 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 1.25 g of chloranil and 1 gof sodium 2,5-dimethylbenzenesulfonate are suspended in 125 ml of2,4-dichlorotoluene. The mixture is then heated. Between 80-100° C.there are added 4 ml of methanesulfonic acid. At around 135-140° C.there are added 4.5 ml of benzenesulfonyl chloride. The reaction mixtureis then heated to 145° C. for 4 hours, cooled to 100° C. and collectedby filtration. The filter cake is washed with 150 ml of hot2,4-dichlorotoluene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 12 g of a green-metallic powder of the following formula.

Yield: 91.6%

EXAMPLE 5

13.2 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 1.25 g of chloranil and 1 gof sodium 2,5-dimethylbenzenesulfonate are suspended in 125 ml of2,4-dichlorotoluene. The mixture is then heated. Between 80-100° C.there are added 9.8 g of benzenesulfonic acid. At around 135-140° C.there are added 4.5 ml of benzenesulfonyl chloride. The reaction mixtureis then heated to 145° C. for 4 hours, cooled to 100° C. and collectedby filtration. The filter cake is washed with 150 ml of hot2,4-dichlorotoluene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 9.3 g of a green-metallic powder of the following formula.

Yield: 71%

EXAMPLE 6

13.2 g of2,5-dichloro-3,6-bis(1-ethyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(as obtained in Reference Example 1a), and 1 g of chloranil and 1 g ofsodium 2,5-dimethylbenzenesulfonate are suspended in 125 ml of2,4-dichlorotoluene. The mixture is then heated. Between 80-100° C.there are added 4 ml of methanesulfonic acid. At around 135-140° C.there are added 6.7 g of toluenesulfonyl chloride. The reaction mixtureis then heated to 145° C. for 4 hours, cooled to 100° C. and collectedby filtration. The filter cake is washed with 150 ml of hot2,4-dichlorotoluene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 12.7 g of a green-metallic powder of the following formula.

Yield: 97%

EXAMPLE 7 One-Pot-Reaction

75.4 g of 5-amino-1-ethyl-1,3-dihydrobenzimidazol-2-one and 19.7 g ofanhydrous sodium hydrogencarbonate are suspended in 1 L of1,2-dichlorobenzene and the mixture is heated up to 82° C. Over a periodof 2 h are added 27 g of chloranil. The mixture is heated for 5 h. Afterthe addition of 24.8 g of sodium 2,5-dimethylbenzenesulfonate thetemperature is raised to 130° C., and 32 ml of methanesulfonic acid areadded. The temperature is then raised to 140° C. and 36 ml ofbenzenesulfonyl chloride are added. The reaction mixture is then heatedfor 3 h at 160° C., cooled to 100° C. and collected by filtration. Thefilter cake is washed with 500 ml of hot 1,2-dichlorobenzene and thensuspended in boiling water, collected by filtration and washed withwater until free of chloride. Drying at 80° C. yielded 80.9 g of agreen-metallic powder of the following formula.

Yield: 77.3%

EXAMPLE 8

12.5 g of2,5-dichloro-3,6-bis(1-methyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(obtained in analogy to Example 1a), and 1.25 g of chloranil aresuspended in 125 ml of 1,2-dichlorobenzene. The mixture is then heated.Between 80-100° C. there are added 4 ml of methanesulfonic acid. Ataround 135-140° C. there are added 4.5 ml of benzenesulfonyl chloride.The mixture is then heated to 145° C. for 4 hours, cooled to 100° C. andcollected by filtration. The filter cake is washed with 150 ml of hot1,2-dichlorobenzene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 10.6 g of a green-metallic powder of the following formula.

Yield: 85.6%

EXAMPLE 9

125 g of2,5-dichloro-3,6-bis(1-methyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(obtained in analogy to Example 1a), and 10 g of chloranil and 31 g ofsodium 2,5-dimethylbenzenesulfonate are suspended in 1250 ml of1,2-dichlorobenzene. The mixture is then heated. Between 80-100° C.there are added 40 ml of methanesulfonic acid. At around 135-140° C.there are added 45 ml of benzenesulfonyl chloride. The mixture is thenheated to 160° C. for 4 hours, cooled to 100° C. and collected byfiltration. The filter cake is washed with 1.5 L of hot1,2-dichlorobenzene and then suspended in boiling water, collected byfiltration and washed with water until free of chloride. Drying at 80°C. yielded 119.8 g of a green-metallic powder of the following formula.

Yield: 96.6%

EXAMPLE 10

12.5 g of2,5-dichloro-3,6-bis(1-methyl-2-oxo-1,3-dihydrobenzimidazol-5-yl)amino-1,4-benzoquinone(obtained in analogy to Example 1a), and 1.25 g of chloranil and 1 g ofsodium 2,5-dimethylbenzenesulfonate are suspended in 125 ml of4-methylanisole. The mixture is then heated. Between 80-100° C. thereare added 4 ml of methanesulfonic acid. At around 135-140° C. there areadded 4.5 ml of benzenesulfonyl chloride and 4.5 ml of benzenesulfonylchloride. The mixture is then heated to 140° C. for 4 hours, cooled to100° C. and collected by filtration. The filter cake is washed with 150ml of hot 4-methylanisole and then suspended in boiling water, collectedby filtration and washed with water until free of chloride. Drying at80° C. yielded 10.5 g of a green-metallic powder of the followingformula

Yield: 85.1%

EXAMPLE 11

130.4 g of 5-amino-1-methyl-1,3-dihydrobenzimidazol-2-one, 141.6 g of5-amino-1-ethyl-1,3-dihydrobenzimidazol-2-one and 134.4 g of anhydroussodium hydrogen-carbonate are suspended in 2.5 L of 1,2-dichlorobenzeneand the mixture is heated up to 82° C. Over a period of 2 h are added197.6 g of chloranil. The mixture is heated for 5 h. After the additionof 50 g of sodium 2,5-dimethylbenzenesulfonate the temperature is raisedto 130° C., and 65 ml of methanesulfonic acid are added. The temperatureis then raised to 140° C. and 72 ml of benzenesulfonyl chloride areadded. The reaction mixture is then heated for 3 h at 155° C., cooled to100° C. and collected by filtration. The filter cake is washed with 1500ml of hot 1,2-dichlorobenzene and then suspended in boiling water,collected by filtration and washed with water until free of chloride.Drying at 80° C. yielded 273 g of a green-metallic powder as a mixtureof the following formula.

R¹=R²=Ethyl R¹=R²=Methyl R¹=Methyl, R²=Ethyl

Yield: 64.7%

The pigments so obtained show excellent pigment properties likedispersibility, color strength, excellent heat and light stability whenapplied in engineering plastics or coatings.

Application of Pigment Blue 80 in a non-ageing finish for automotiveupholstery.

Automotive crust leather is furnished with a bottom coat employing thefollowing mixture

600 g of a binder combination composed of a polyurethane-binder and apolyacrylate-binder300 g of an additive combination composed of fillers and wax-dispersions

100 g of Pigment Blue 80

This mixture is applied by spray dyeing (coating quantity 60 g/m²),dried, hot pressed at 90° C. at 50 bar in a through-feed process,followed by 6 h of milling.

On top of this bottom layer a colour coat consisting of

550 g of a binder combination composed of a polyurethane-binder and apolyacrylate-binder220 g of an additive combination composed of fillers and wax-dispersions

100 g of Pigment Blue 80

110 g of water20 g of a cross-linking agent based on isocyanateis applied by spray dyeing (coating quantity 25 g/m²) and dried

Finally a top finish consisting of

450 g of a delustered polyurethane-dispersion140 g of a binder combination composed of a polyurethane-binder and apolyacrylate-binder220 g of an additive combination composed of fillers and wax-dispersions270 g of water70 g of an additive combination composed of siloxane emulsions andwash-dispersions70 g of a cross-linking agent based on isocyanateis applied twice by spray dyeing (coating quantity 20 g/m²) and driedafter every application.

1. A process for the preparation of a compound of the general formula(I)

wherein X are halogen atoms, the rings labeled A are linearly orangularly fused in position 1,2; 2,3 or 3,4, and in position 8,9; 9,10or 10,11, to a 5- or 6-membered heterocyclic ring containing in the ringone nitrogen atom and one oxygen atom, or containing in the ring twonitrogen atoms, comprising the step of oxidating a3,6-bisarylamino-2,5-dihalobenzoquinone of the formula (II)

in one or more aprotic-polar organic solvents in the presence of anorganic sulfonic acid.
 2. The process as claimed in claim 1, wherein thecompounds of formula (I) are those with formulae (Ia), (IIa), (IIIa) and(IIIb)

where X is hydrogen or halogen, R₁, R₂, R₃ and R₄, independently fromone another, are hydrogen, a C₁₋₈ alkyl radical, a substituted orunsubstituted phenyl, benzyl, benzanilide or naphthyl radical, asubstituted or unsubstituted C₅₋₆ cycloalkyl radical.
 3. The process asclaimed in claim 1 wherein the one or more aprotic-polar organicsolvents are ethers, esters, ketones, amines, nitromethane,chlorobenzenes, chlorotoluenes, or a mixture thereof.
 4. The process asclaimed in any of claims 1, wherein the one or more aprotic-polarsolvents are selected from the group consisting of chlorobenzene,1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 2-chlorotoluene, 3-chloro toluene, 4-chloro toluene, 2,4-dichloro toluene,3-methyl anisol, 4-methyl anisol, and nitromethane.
 5. The process asclaimed in claim 1, wherein the organic sulfonic acid is selected fromthe group consisting of methane sulfonic acid, benzene sulfonic acid,toluene sulfonic acid and xylene sulfonic acid.
 6. The process asclaimed in claim 1, wherein the organic sulfonic acid is used in anamount from 10 to 360 mol %, based on the compound of formula (II). 7.The process as claimed in claim 1, wherein the oxidation is performed ata temperature of 120 to 160° C.
 8. The process as claimed in claim 1,wherein the oxidation is carried out by benzenesulfonylchloride,toluenesulfonylchloride, chloranil or a mixture thereof.